Roof pitch indicator



Dec. 10, 1935. F. M. PACKARD 2,023,539

ROOF PITCH INDICATOR Filed Oct. 20, 1955 FIG 1 l B mnmw M ATTORNEY.

Patented Dec. 10, 1935 UNITED STATES @ATENT OFFIQE ROOF PITCH INDICATORFrancis M. Packard, Davenport, Iowa Application October 20, 1933, SerialNo. 694,497 1 Claim. (01. 33-75) My invention has reference to aninstrument for indicating the pitch of a roof, and making variouscomputations in connection therewith. By its use it is possible to makean estimate of the pitch or" a roof from the ground, to compute thelength of the rafters, and the area of the roof. It is of specialadvantage in determining the amount of roofing material required forreplacing an old roof. At the present time the only method for doingthis which is in practice is to go upon the roof and make the necessarymeasurements.

The instrument consists or" a pair of arms pivotaily attached to eachother, and provided with a head on one of said arms having graduatedtables, and a disk on the other arm provided with indicators for use inmaking readings on said tables. The arms are also provided with tablespertaining to the general roof characteristics, and various data for usein making the desired computations. The character of the device is suchthat it can be used as a sight instrument initially in determining thepitch of a roof at a little distance therefrom. By the use of the tablesmentioned it is also possible to set the instrument for use in makingplumb cuts of rafters and other cuts on lumber going into a roof. Thetables on the arms of the instrument are of a four-fold character,making it possible to include therein data for roofs varying from athree-inch pitch to a twenty-four-inch pitch.

Another feature of the invention consists in a protractor table on thehead of the instrument, which can be used independently of the othertables for securing various angles, and can also be used in connectionwith said other tables in making computations or verifying the same.

Another advantage of the invention consists in the facility with whichit can be folded into a small space, for carrying in the pocket or in atool box. It also possesses advantages as an advertising medium, beingprovided with spaces which can be used for commercial cards.

The above named, and other features and advantages of the invention willmore fully appear from the following specification, taken in connectionwith the accompanying drawing, in which:

Fig. 1 is a plan view, showing the invention with the arms of the toolin angular relation, as when in use.

Fig. 2 shows the same with the arms describing a smaller angle, as whena larger angle is bi sected for laying out a plumb-cut of a rafter.

Fig. 3 is a fractional view of the head 6, showing the plumb-cut scale,enlarged.

The instrument consists of an arm 5, provided at one end with a head 6of circular form, and a similar arm 1, provided at one end with a disk8, pivotally connected with the head 6 by a rivet 9, so that said headand disk have a frictional engagement with each other. The edges 80 andI! {g of the arm 5 are in parallel relation with each other, and can beused as straight edges, and the edge it is in line with the pivot 9. Theedges l2 and E3 of the arm i are also in parallel relation with eachother, and the edge 53 is in line with 3} said pivot. The diameter ofthe disk 8 is less than that of the head 6, the space on the projectingportion of the head being utilized for tables of graduated scales, as ishereinafter more fully set forth. l5 The arms 5 and l are shown providedwith four tables of numbers, as at A, B, C, and D, each table beingformed of columns of spaces transversely of the arms, as noted at a, b,c, d, e, f, and g, the columns being repeated in the several tables, so20 as to allow for the listing of a number of variations in roof pitchesand other designations. Said columns are subdivided by longitudinallines into spaces for the numbers, and are variously designated at theheads of the columns. The 25 first of said columns is marked Rise perfoot run, which is indicative of the pitch of a roof, and the secondcolumn gives the roof pitch as commonly termed. For instance, in TableC, in the last space the rise per foot run is given as 30 18 inches, andin the second column it is set forth as a three-fourths pitch. On thehead 6 at E is a table provided with markings corresponding with thevarious pitches, readable by means of a pointer M on the edge of thedisk 8, and show- 35 ing that the angular inclination of the arms 5 and'5 corresponds with the pitch of a roof. These markings correspond withthe figures in column a of the tables, and these are the key figuresupon which various deductions and computations may 40 be made.

If it is desired to find the pitch of a roof from the outside of abuilding the instrument is held by the operator with the ends of thearms pointed downwardly while the operator sights at the gable 45 end ofthe roof along the inner edges of said arms, and moves the same untilthey correspond in position with the edges of the roof. 'Lhe degree ofvariation of the arms as well as the pitch of the roof is thereuponindicated by the pointer M on the scale E, which is shown in the drawingset for a 14 inch pitch. This is then used as a basis for making desiredcomputations. The head 6 is also provided with a protractor scale F, tobe used in connection with a pointer I5 on the edge of the disk 8.

The arms 5 and l are rotatable in adjacent planes, so that said bladescan be made to cross over each other, and when in a normally foldedposition the edges IE! and I3 are adjacent to each other and the edges lI and I2 on the outside, and parallel with each other. For sightingpurposes the arms are crossed over, as in Fig. 1, with the edges H and12 on the inside and forming a complete angle, which can be varied toform any acute or obtuse angle. The edges 60 and I3 can not be used forforming a sight ing angle, on account of obstructions near the innerends thereof.

After finding the pitch of a roof in the manner hereinbefore set forththe length of a common rafter in such roof may be determined by the useof measurements contained in column d of the tables on the arms. This isdone by measuring the width of the building including cornices, andmultiplying one-half of this dimension by the number in said columnwhich is in line withthe pitch indicated. For example, assuming thewidth of the building to be twenty-eight feet including the cornices,one-half of this amount, if for a 14 inch pitch, is multiplied by 1.536,giving the length of the rafter as approximately 21.5 feet.

In case the roofing on such roof is to be replaced, and it is desired tofind the area of the roof, this is done by multiplying the width of thebuilding by the length of such building, including the cornices, andadding to the amount thus attained a percentage thereof, as contained incolumn e. For example, assuming the building to be the same width asgiven above, and the length thereof forty feet, the forty is multipliedby the 28, giving as a'result 1120 square feet, and if the pitch of theroof is 14 inches, this amount has added thereto fifty-four per cent ofsaid amount, or 604.8 square feet. This amount is then added to theoriginal amount, giving the sum of 1725 square feet, the total area ofthe roof. In this computation no allowance is made for waste.

A similar computation to that given above for a common rafter may bemade for obtaining the length of a hip or valley rafter, by the use offigures in column 1 of the tables. For a building of the same width asbefore given and having a 12 inch pitch, one half of the width ismultiplied by 1.83, giving a rafter length of 24.22 feet. The sameresult may be obtained by adding to the length of a common rafter forthe same roof a percentage as shown in column 9. In the case of a 12inch pitch this is 22 per cent. In making any measurement of raftersthere is no allowance for plumb cuts thereof.

In the case of a building under construction the computationshereinbefore mentioned can be made and the rafters and roofing materialcut to desired dimensions before taking them on the building. Theinstrument can also be used for making markings on the rafters formaking miter cuts thereon, such as a plumb cut at the upper end of arafter and a heel-cut at the lower end. For both of these operations thescale F may be employed, and in addition thereto a scale G on the head6. readable with an arrow I 6 on the disk 8. The divisions on said scaleare shown numbered from 1 to 24, and they coincide in position withabout sixty degrees of thelprotractor scale. They also correspond withthe roof scale numbers in the tables on the arms. The setting of thetool is made in accordance with the data contained in column of thetables, which are marked for degrees on the scale F, and constantlyincreasing as the pitch increases.

In establishing the position of the arms for a heel-cut marking thepointer 15 is made use of, and with the markings at the lower end of thescale F. For a 14. inch rise the indication in column c is approximately49 degrees, and the pointer is set at this point on the scale, givingthe desired angle to the arms. The marking is then done by placing theinner edge of one of said arms against the edge of the timber and usingthe adjacent edge of the other arm as a straightedge, for marking acrossthe face of the timber.

For a plumb-cut marking the indicator I6 is used, with the degrees atthe upper end of the scale. The positions of the degrees on the scaleshould be reversed for this reading, but the desired result is obtainedby subtracting the number of degrees shown in column 0 from the totalnumber of the degrees, and using the remaining figure as a gauge for theindicator. For example, in the 14 inch pitch, the table gives a settingof approximately 50 degreea'and this amount is deducted from 180,leaving 130 as the point for locating the indicator. When at this pointthe indicator will also be in line with the number 14 on the scale G.The setting of the indicator on thescale G is thereby verified by thedegree marking on the scale F, and this will be the case with all of themarkings on the scale G.

The markings on the scale G are on a larger circumference and havesmaller divisions, making it possible to make finer settings than on thescale F alone. When the angle has been 3 established the instrument isset against the rafter as before, and in position to make a mitermarking in the opposite direction, and at substantially right angleswith the heel-cut marking.

The device can also be used for finding the 40.

angle of an object of angular formation by fitting the inner edges ofthe arms 5 and 1 against the object and noting the degree of separationof the arms on the scale F.

The arms are shown extended beyond the table 45. markings forconvenience in handling, with spaces l8 at the ends for reading matter,such 'as instructions for using the instrument or for advertising cards.The reverse faces of said arms can also be made use of for similarpurposes. 50.

The instrument is preferably formed of celluloid with the variousmarkings stamped or printed thereon, and the arms can be folded intoparall'el relation as shown in broken lines in Fig.

1, for convenience in carrying in the pocket or other receptacle. Othermaterial than that mentioned can be used in the construction of thedevice, and changes can be made in the arrangement'of the various scalesand tables without departing from the general purpose thereof.

What I claim, anddesire to secure by Letters Patent, is:

A roof pitch indicator comprised of a pair of arms pivotally united attheir ends and rotatable in adjacent planes, having a pair of edges inline with the pivotal point, and a pair of straight edges parallel withthe first-named edges, said arms being foldable to bring the last-namededges into parallel relation with each other, and

also movable to cause said last-named edges to form a perfect angle, andcooperating means on said arms for indicating the degree or roof pitchshown by said angle.

FRANCIS M. PACKARD.

